PROJECT SUMMARY/ABSTRACT Background: A persistent ~10% of new U.S. HIV infections occur among people who inject drugs (PWID). Provision of sterile syringes (via syringe service programs [SSPs] and pharmacies) helps prevent injection- related HIV transmission; however, syringe access is insufficient in many locations, and the majority of PWID experience substantial overlapping sexual and injection-related HIV risks. As in several geographic regions of the United States, in the Northeast, increasing injection of opioids, stimulants, and other drugs is causing renewed concerns about HIV transmission, with CDC declaring HIV outbreaks connected to injection drug use. Despite the proven efficacy of pre-exposure prophylaxis (PrEP) and U.S. Preventive Services Task Force recommendation that PrEP be offered to PWID at risk for HIV acquisition, uptake in this socially marginalized population remains severely limited. Overview of Proposal: The current proposal is a culmination of extensive preliminary research, including (a) in-depth qualitative research with PWID across Northeastern communities affected by opioid use and HIV that documented high HIV risk and low PrEP knowledge but high interest, (b) key informant interviews with PrEP providers, SSP staff, and other key stakeholders who provided specific suggestions for PrEP intervention content and delivery strategies, and (c) two pilot randomized controlled trials (RCTs) of PrEP Navigator-delivered behavioral interventions with high risk populations including people who use drugs and PWID that demonstrated the feasibility, acceptability, and preliminary efficacy of our proposed approach. This extensive research has led to the development of the ?PrEP for Health? intervention. Conceptual Model: ?PrEP for Health? is a brief, multi-component behavioral intervention delivered to PWID by highly trained PrEP Navigators embedded within SSPs that seeks to improve PrEP uptake (primary outcome) and PrEP adherence and persistence (secondary outcomes) among PWID by increasing HIV and PrEP knowledge, improving HIV risk perceptions and PrEP interest and motivation, cultivating PrEP use self-efficacy and behavioral skills, and reducing structural barriers to PrEP use. Overview of Study Design: We propose testing efficacy of ?PrEP for Health? in two SSPs in Lawrence and Boston/Cambridge, Massachusetts, areas heavily affected by injection-related HIV transmission. We will equally randomize 200 PWID to receive either (a) the ?PrEP for Health? intervention, which includes Navigator-delivered, theory-informed HIV and PrEP education, motivational interviewing, problem-solving and planning, and ongoing PrEP navigation (n=100), or (b) standard of care (information and referrals; n=100). We will evaluate successful PrEP uptake (via medical/pharmacy records), adherence (via drug levels in hair), and persistence (via medical/ pharmacy records) over 12 months. We will also examine the degree to which intervention efficacy occurs through specific conceptual mediators (e.g., PrEP knowledge, motivation, self-efficacy) and differs according to hypothesized moderators (e.g., age, gender, sexual risk).